// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org       
 */

#include <linux/platform_device.h>
#include <linux/slab.h>
#include "tpm.h"

/* National definitions */
enum tpm_nsc_addr{
        TPM_NSC_IRQ = 0x07,
        TPM_NSC_BASE0_HI = 0x60,
        TPM_NSC_BASE0_LO = 0x61,
        TPM_NSC_BASE1_HI = 0x62,
        TPM_NSC_BASE1_LO = 0x63
};

enum tpm_nsc_index {
        NSC_LDN_INDEX = 0x07,
        NSC_SID_INDEX = 0x20,
        NSC_LDC_INDEX = 0x30,
        NSC_DIO_INDEX = 0x60,
        NSC_CIO_INDEX = 0x62,
        NSC_IRQ_INDEX = 0x70,
        NSC_ITS_INDEX = 0x71
};

enum tpm_nsc_status_loc {
        NSC_STATUS = 0x01,
        NSC_COMMAND = 0x01,
        NSC_DATA = 0x00
};

/* status bits */
enum tpm_nsc_status {
        NSC_STATUS_OBF = 0x01,  /* output buffer full */
        NSC_STATUS_IBF = 0x02,  /* input buffer full */
        NSC_STATUS_F0 = 0x04,   /* F0 */
        NSC_STATUS_A2 = 0x08,   /* A2 */
        NSC_STATUS_RDY = 0x10,  /* ready to receive command */
        NSC_STATUS_IBR = 0x20   /* ready to receive data */
};

/* command bits */
enum tpm_nsc_cmd_mode {
        NSC_COMMAND_NORMAL = 0x01,      /* normal mode */
        NSC_COMMAND_EOC = 0x03,
        NSC_COMMAND_CANCEL = 0x22
};

struct tpm_nsc_priv {
        unsigned long base;
};

/*
 * Wait for a certain status to appear
 */
static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);
        unsigned long stop;

        /* status immediately available check */
        *data = inb(priv->base + NSC_STATUS);
        if ((*data & mask) == val)
                return 0;

        /* wait for status */
        stop = jiffies + 10 * HZ;
        do {
                msleep(TPM_TIMEOUT);
                *data = inb(priv->base + 1);
                if ((*data & mask) == val)
                        return 0;
        }
        while (time_before(jiffies, stop));

        return -EBUSY;
}

static int nsc_wait_for_ready(struct tpm_chip *chip)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);
        int status;
        unsigned long stop;

        /* status immediately available check */
        status = inb(priv->base + NSC_STATUS);
        if (status & NSC_STATUS_OBF)
                status = inb(priv->base + NSC_DATA);
        if (status & NSC_STATUS_RDY)
                return 0;

        /* wait for status */
        stop = jiffies + 100;
        do {
                msleep(TPM_TIMEOUT);
                status = inb(priv->base + NSC_STATUS);
                if (status & NSC_STATUS_OBF)
                        status = inb(priv->base + NSC_DATA);
                if (status & NSC_STATUS_RDY)
                        return 0;
        }
        while (time_before(jiffies, stop));

        dev_info(&chip->dev, "wait for ready failed\n");
        return -EBUSY;
}


static int tpm_nsc_recv(struct tpm_chip *chip, u8 * buf, size_t count)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);
        u8 *buffer = buf;
        u8 data, *p;
        u32 size;
        __be32 *native_size;

        if (count < 6)
                return -EIO;

        if (wait_for_stat(chip, NSC_STATUS_F0, NSC_STATUS_F0, &data) < 0) {
                dev_err(&chip->dev, "F0 timeout\n");
                return -EIO;
        }

        data = inb(priv->base + NSC_DATA);
        if (data != NSC_COMMAND_NORMAL) {
                dev_err(&chip->dev, "not in normal mode (0x%x)\n",
                        data);
                return -EIO;
        }

        /* read the whole packet */
        for (p = buffer; p < &buffer[count]; p++) {
                if (wait_for_stat
                    (chip, NSC_STATUS_OBF, NSC_STATUS_OBF, &data) < 0) {
                        dev_err(&chip->dev,
                                "OBF timeout (while reading data)\n");
                        return -EIO;
                }
                if (data & NSC_STATUS_F0)
                        break;
                *p = inb(priv->base + NSC_DATA);
        }

        if ((data & NSC_STATUS_F0) == 0 &&
        (wait_for_stat(chip, NSC_STATUS_F0, NSC_STATUS_F0, &data) < 0)) {
                dev_err(&chip->dev, "F0 not set\n");
                return -EIO;
        }

        data = inb(priv->base + NSC_DATA);
        if (data != NSC_COMMAND_EOC) {
                dev_err(&chip->dev,
                        "expected end of command(0x%x)\n", data);
                return -EIO;
        }

        native_size = (__force __be32 *) (buf + 2);
        size = be32_to_cpu(*native_size);

        if (count < size)
                return -EIO;

        return size;
}

static int tpm_nsc_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                        size_t count)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);
        u8 data;
        int i;

        /*
         * If we hit the chip with back to back commands it locks up
         * and never set IBF. Hitting it with this "hammer" seems to
         * fix it. Not sure why this is needed, we followed the flow
         * chart in the manual to the letter.
         */
        outb(NSC_COMMAND_CANCEL, priv->base + NSC_COMMAND);

        if (nsc_wait_for_ready(chip) != 0)
                return -EIO;

        if (wait_for_stat(chip, NSC_STATUS_IBF, 0, &data) < 0) {
                dev_err(&chip->dev, "IBF timeout\n");
                return -EIO;
        }

        outb(NSC_COMMAND_NORMAL, priv->base + NSC_COMMAND);
        if (wait_for_stat(chip, NSC_STATUS_IBR, NSC_STATUS_IBR, &data) < 0) {
                dev_err(&chip->dev, "IBR timeout\n");
                return -EIO;
        }

        for (i = 0; i < count; i++) {
                if (wait_for_stat(chip, NSC_STATUS_IBF, 0, &data) < 0) {
                        dev_err(&chip->dev,
                                "IBF timeout (while writing data)\n");
                        return -EIO;
                }
                outb(buf[i], priv->base + NSC_DATA);
        }

        if (wait_for_stat(chip, NSC_STATUS_IBF, 0, &data) < 0) {
                dev_err(&chip->dev, "IBF timeout\n");
                return -EIO;
        }
        outb(NSC_COMMAND_EOC, priv->base + NSC_COMMAND);

        return 0;
}

static void tpm_nsc_cancel(struct tpm_chip *chip)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);

        outb(NSC_COMMAND_CANCEL, priv->base + NSC_COMMAND);
}

static u8 tpm_nsc_status(struct tpm_chip *chip)
{
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);

        return inb(priv->base + NSC_STATUS);
}

static bool tpm_nsc_req_canceled(struct tpm_chip *chip, u8 status)
{
        return (status == NSC_STATUS_RDY);
}

static const struct tpm_class_ops tpm_nsc = {
        .recv = tpm_nsc_recv,
        .send = tpm_nsc_send,
        .cancel = tpm_nsc_cancel,
        .status = tpm_nsc_status,
        .req_complete_mask = NSC_STATUS_OBF,
        .req_complete_val = NSC_STATUS_OBF,
        .req_canceled = tpm_nsc_req_canceled,
};

static struct platform_device *pdev = NULL;

static void tpm_nsc_remove(struct device *dev)
{
        struct tpm_chip *chip = dev_get_drvdata(dev);
        struct tpm_nsc_priv *priv = dev_get_drvdata(&chip->dev);

        tpm_chip_unregister(chip);
        release_region(priv->base, 2);
}

static SIMPLE_DEV_PM_OPS(tpm_nsc_pm, tpm_pm_suspend, tpm_pm_resume);

static struct platform_driver nsc_drv = {
        .driver          = {
                .name    = "tpm_nsc",
                .pm      = &tpm_nsc_pm,
        },
};

static inline int tpm_read_index(int base, int index)
{
        outb(index, base);
        return inb(base+1) & 0xFF;
}

static inline void tpm_write_index(int base, int index, int value)
{
        outb(index, base);
        outb(value & 0xFF, base+1);
}

static int __init init_nsc(void)
{
        int rc = 0;
        int lo, hi, err;
        int nscAddrBase = TPM_ADDR;
        struct tpm_chip *chip;
        unsigned long base;
        struct tpm_nsc_priv *priv;

        /* verify that it is a National part (SID) */
        if (tpm_read_index(TPM_ADDR, NSC_SID_INDEX) != 0xEF) {
                nscAddrBase = (tpm_read_index(TPM_SUPERIO_ADDR, 0x2C)<<8)|
                        (tpm_read_index(TPM_SUPERIO_ADDR, 0x2B)&0xFE);
                if (tpm_read_index(nscAddrBase, NSC_SID_INDEX) != 0xF6)
                        return -ENODEV;
        }

        err = platform_driver_register(&nsc_drv);
        if (err)
                return err;

        hi = tpm_read_index(nscAddrBase, TPM_NSC_BASE0_HI);
        lo = tpm_read_index(nscAddrBase, TPM_NSC_BASE0_LO);
        base = (hi<<8) | lo;

        /* enable the DPM module */
        tpm_write_index(nscAddrBase, NSC_LDC_INDEX, 0x01);

        pdev = platform_device_alloc("tpm_nscl0", -1);
        if (!pdev) {
                rc = -ENOMEM;
                goto err_unreg_drv;
        }

        pdev->num_resources = 0;
        pdev->dev.driver = &nsc_drv.driver;
        pdev->dev.release = tpm_nsc_remove;

        if ((rc = platform_device_add(pdev)) < 0)
                goto err_put_dev;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv) {
                rc = -ENOMEM;
                goto err_del_dev;
        }

        priv->base = base;

        if (request_region(base, 2, "tpm_nsc0") == NULL ) {
                rc = -EBUSY;
                goto err_del_dev;
        }

        chip = tpmm_chip_alloc(&pdev->dev, &tpm_nsc);
        if (IS_ERR(chip)) {
                rc = -ENODEV;
                goto err_rel_reg;
        }

        dev_set_drvdata(&chip->dev, priv);

        rc = tpm_chip_register(chip);
        if (rc)
                goto err_rel_reg;

        dev_dbg(&pdev->dev, "NSC TPM detected\n");
        dev_dbg(&pdev->dev,
                "NSC LDN 0x%x, SID 0x%x, SRID 0x%x\n",
                tpm_read_index(nscAddrBase,0x07), tpm_read_index(nscAddrBase,0x20),
                tpm_read_index(nscAddrBase,0x27));
        dev_dbg(&pdev->dev,
                "NSC SIOCF1 0x%x SIOCF5 0x%x SIOCF6 0x%x SIOCF8 0x%x\n",
                tpm_read_index(nscAddrBase,0x21), tpm_read_index(nscAddrBase,0x25),
                tpm_read_index(nscAddrBase,0x26), tpm_read_index(nscAddrBase,0x28));
        dev_dbg(&pdev->dev, "NSC IO Base0 0x%x\n",
                (tpm_read_index(nscAddrBase,0x60) << 8) | tpm_read_index(nscAddrBase,0x61));
        dev_dbg(&pdev->dev, "NSC IO Base1 0x%x\n",
                (tpm_read_index(nscAddrBase,0x62) << 8) | tpm_read_index(nscAddrBase,0x63));
        dev_dbg(&pdev->dev, "NSC Interrupt number and wakeup 0x%x\n",
                tpm_read_index(nscAddrBase,0x70));
        dev_dbg(&pdev->dev, "NSC IRQ type select 0x%x\n",
                tpm_read_index(nscAddrBase,0x71));
        dev_dbg(&pdev->dev,
                "NSC DMA channel select0 0x%x, select1 0x%x\n",
                tpm_read_index(nscAddrBase,0x74), tpm_read_index(nscAddrBase,0x75));
        dev_dbg(&pdev->dev,
                "NSC Config "
                "0x%x 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x\n",
                tpm_read_index(nscAddrBase,0xF0), tpm_read_index(nscAddrBase,0xF1),
                tpm_read_index(nscAddrBase,0xF2), tpm_read_index(nscAddrBase,0xF3),
                tpm_read_index(nscAddrBase,0xF4), tpm_read_index(nscAddrBase,0xF5),
                tpm_read_index(nscAddrBase,0xF6), tpm_read_index(nscAddrBase,0xF7),
                tpm_read_index(nscAddrBase,0xF8), tpm_read_index(nscAddrBase,0xF9));

        dev_info(&pdev->dev,
                 "NSC TPM revision %d\n",
                 tpm_read_index(nscAddrBase, 0x27) & 0x1F);

        return 0;

err_rel_reg:
        release_region(base, 2);
err_del_dev:
        platform_device_del(pdev);
err_put_dev:
        platform_device_put(pdev);
err_unreg_drv:
        platform_driver_unregister(&nsc_drv);
        return rc;
}

static void __exit cleanup_nsc(void)
{
        if (pdev) {
                tpm_nsc_remove(&pdev->dev);
                platform_device_unregister(pdev);
        }

        platform_driver_unregister(&nsc_drv);
}

module_init(init_nsc);
module_exit(cleanup_nsc);

MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");